Stitch-forming mechanism for sewing machines



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A. F. FIFIELD STITCH FORMING MECHANISM FOR SEWING MACHINES 19 3 5 Sheets-Sheet 1 Filed Feb. 20

INVENTOR m 2f WITNESSES J ATTORNEY Nov. 11 1929 A. F. FlFlELD STITCH FORMING MECHANISM FOR SEWING MACHINES Filed Feb. 20, 1923 5 Sheets-Sheet 2 INVE NTOR wff b'a WiTNESSES ATTORN EY Nov. 11 1924 r A. F. FIFIELD STITCH FORMING MECHANISM FOR SEWING MACHINES Filed Feb. 20. 19 3 5 Sheets-Sheet INVENTOR zygnrz 'ATTORNEY N & M\

WITNESSES NOV. 1920 A. F. FIFIELD STITCH FORMING MECHANISM FOR SEWING MACHINES Filed Feb. 20 1923 5 Sheets-Sheet 4 ATTORNEY A. F. FlFlELD STITCH FORMING MECHANISM FOR SEWING MACHINES Nov. 11 f Filed Fe 20. 19 5 5 Sheets-Sheet 5 INVENT OR WITNESSES Patented Nov. 11, 1924.

UNITED STATES PATENT OFFICE.

ALBERT F. FHIELD, OF NEWARK, NEW JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, OF ELIZABETH, NEW JERSEY, A CORPORATION OF NEW JERSEY.

STITCH-FORMING MECHANISM FOR SEWING- MACHINES.

Application filed February 20, 1923. Serial No. 620,174.

To all whom it may concern:

Be it known that I, ALBERT F. FIFIELD, a citizen of the United States, residing at Newark, in the county of Essex and'State of New Jersey, have invented certain new and useful Improvements in Stitch-Forming Mechanisms for Sewing Machines, of which the following is a specification, reference being had therein to the accompanying drawm s.

lhis invention relates generally to sewing machines and more particularly to singlethread chain-stitch machines having a looper of the rotary type such as disclosed in the patent to Gibbs, No. 17,427 of June 2, 1857, or in my Patent No. 1,316,022, of Sept. 16, 1919.

Loopers of'this type are constructed with a loop-seizing beak and a loop-deflecting or loop-spreading wing, sometimes called a castoif'spur, which engages the seized needle-loop after the looper-beak has rotated about "180 past loop-seizing position and gives such loop a half-twist,thereafter holding such half-twisted loop spread for passage of the looper-beak with a new needle-loop through the half-twisted and spread loop the latter being thereupon released by the wing of the looper and drawn up to the work or tightened as the new loop is distended by the looper.

It is characteristic of all straightaway sewing by machines of this type (i. e. sewing when the work is fed continuously off of the looper-beak WhlCh'lS generally understood to mean in the same direction the looper-beak is moving when seizing a needle-loop) that the loops are half-twisted as shown in an exaggerated way in Fig. of said Gibbs patent. In practice, however, the single crossings of the limbs of the halftwisted loops are not generally noticeable at the under side of the work, since such crossings tend to assume positions at the nee-.

rile-punctures rather than between the me dle-punctures as shown by Gibbs.

Since the introduction of the rotary chainstitch looper, machines of this type have been adapted for various sewing operations, necessitating the feeding of the work in vathe looper,

rious directions other than off of the looperbeak. These other directions of feed are customarily referred to as onto the looper beak (i. e. opposite to the direction in which the looper-beak is moving when seizing a needle-loop); onto the loopershaft (i. e. in a direction lengthwise of the The various sewing operations contemplated include sewing price tickets on clothing by a group of stitches, for example, in the form of a triangle, and sewing on buttons both twohole and four-hole, the two hole buttons being fed either longtudinally or transversely of the looper-shaft and the I four-hole buttons being fed to produce either parallel or crossed diagonal groups 0 stitches. Certain of the operations contemplated necessitate the feeding of the work in diagonal directions having components both parallel and at right an les to the plane of rotation of the looper-beak.

It has long been recognized that a machine equipped with the ordinary rotary chain-stitch looper will sew only when the work is fed oif of the looper-beak; this di rection of feed being essential'in order that the limbs of the previous needle-loop may be carried by the feed of the work to the rear of. the needle-path so that the needle may descend in front of the limbs of the previous needle-loop and in position for the new needle-loop to be seizedxby the looper-beak loop.

prior art have, however, beenadapted for sewing on buttons, tacking, etc., by equipping them with a loop-deflector for engaging the limbs of the needle-loop on regardless of the direction of feed. of the work, and carrying them to the Certain rotary looper machines I of the and passed through the previous needletwist of the needle-loop introduces consider-' able friction between the limbs thereof, as

rear of the needle -or to the same position to which they would be normally carried by the feed of the work in ordinary straightaway sewing; the loop-deflector serving to restore the proper relative positions of the old and new needle-loops lost when the work is fed in directions other than ofl' of the looper-beak.

The application of a loop-deflector to the machine, as done in the prior art, has made it more difficult to draw up the needle-loops shed by the looper; it being necessary to use thread of a good quality which will stand a stronger tension than that to which the thread is subjected in straightaway sewing. It has been noticed in prior machines that when the feed of the work is either onto the looper-beak or oil of the looper-shaft or at any angle intermediate these extremes, the half-twisted needle-loop on the looper assumes a further half-twist, totaling a full twist, when released by the loop-deflector preparatory to being drawn up. This full well as a tendency for such limbs to kink and snarl to such an extent that a considerable tension is required to tighten such loops. Such tension often causes the thread to cut into the work, as when sewing paper tickets on clothing and moreover the thread is often broken. Still further, the work, particularly buttons sewed on by prior machines, presents an unsightly appearance on the under side due to the piling up of the poorly tightened full twisted loops.

The present invention has for an object to provide stitch-forming mechanism of the rotary looper chain-stitch type which will sew when the work is fed in opposite directions either in or across the plane of movement of the looper-beak.

A further object of the invention is to provide stitch-forming mechanism of the rotary looper chain-stitch type which will sew under these conditions without subjecting the thread to heavy tension.

Still further, the invention has for an object to provide stitch-forming mechanism of the rotary looper type which will sew when the work is fed either onto the looper-beak or oil of the looper-shaft or in any direction at an angle intermediate these extremities, without a resultant twist of the needle-loops.

Still further the invention has for an object to provide stitch-forming mechanism of the rotary looper chain-stitch. type which will sew on buttons, either two-hole or four-hole, the latter with either parallel or crossed diagonal stitches, without subjecting any of the loops to a full twist.

Further objects of the invention will appear from the following description and claims.

To the attainment of the ends in view, a

.fore, but behind the portions of the limbs of the needle-loop between the loop-deflector and the last stitch in the work. From this V condition flows a peculiar result, to wit: when a half-twisted needle-loop is released by the loop-deflector, such loop will untwist as it is being drawn up instead of twisting up further, and may be fully and easily tightened under a light strain on the thread; there being no tendency of the thread to snarl or kink. In other words, by virtue of the present improvement, when the work is fed in a direction having components directed onto the looper-beak and off of the looper-shaft, a half-twist is subtracted from the half-twist normally given the needle-loop by the looper, resulting in no twist, whereas in the machines of the prior art a half-twist is added to the half-twist initially produced by the looper,

resulting in a full twist which is objectionable for the reasons stated.

In the accompanying drawings, Fig. l is a side elevation of a sewing machine embodying the invention. Fig. 2 is an enlarged side elevation, partly in section, of the elements of the machine adjacent the sewing point. Fig. 2 is a development of a cam shown in Fig. 2.. Fig. 3 is a bottom plan view of the parts shown in Fig. 2. Fig. 4 is an end elevation of the parts shown in Fig. 2. Fig. 5 is a section on the line 5-5, Fig. 2. Figs. 6, 6", 6, are a 'group of figures lllustrating in end elevation, side elevation and top plan, respectively, the sewing on of a two-hole button by the stitch-forming mechanism of the present improvement, the direction of feed for the particular stitch shown being off of the looper-shaft. Fig. 6 is a diagrammatic view accompanying Fig. 6 to show the shed needle-loop after it is drawn up. Figs. 6 and 6 are views similar to Figs. 6 and 6",

respectively, at a later stage when the looper 1s seizing a new needle-loop.

Figs. 7 7", 7 and 7 area similar group of figures illustrating the sewing of the next succeeding stitch in a two-hole button, the direction of feed being onto the loopershaft.

Figs. 8", 8", 8 and 8 illustrate the sewing on of a two-hole button, the direction of feed being onto the looper-beak and Fi s. 9", 9*, 9 and 9 illustrate the sewing on o a two-hole button, the direction of feed being off of the looper-beak.

Figs. 10, 10; 11, 11 12, 12 and 13, 13 illustrate the sewing on of a four-hole stationary thread-eye 38 and between the latter and the intermittent tension device 37. Its function is to pull a supply of slack- -thread through the open intermittent tension device 37 when the machine is stationary and the clamp is lifted to release the work. The supply of slack pulled by the hook 41 is available at the beginning of a new sewing operation when the upper clamping member has been lowered upon the work. This supply of slack enables the sewing operation to be started, without pulling the beginning thread end out of the usual thread end gripper (not shown) beneath the throat-plate 42.

Journaled in the bearing lugs 16, 16", in the bed of the machine, below the loopershaft 16, is the needle-guide shaft 43 on the forward free end of which is mounted the curved finger 44 constituting a needle-guide similar in function to that disclosed in my Patent No. 1,147,386, of July 20, 1915. This finger is moved rapidly to dotted line position, Fig. 4, by a rocking movement of the shaft 43 when the looper-beak has approached to within about 45 of loop-seizing position and insures against deflection of the needle into the path of the looperbeak. The finger 44 is rapidly returned to full .line position .as soon as the looper has seized the needle-loop. The shaft 43 has secured thereto an arm 45 carrying a roller 46 which is maintained in engagement with the actuating cam 47 on the looper-shaft 16 by means of a torsion sprin 48 coiled upon the shaft 43 and anchored at one end to the bearing lug 16" and at its opposite end to a collar 49 fixed to the shaft 43. The collars 50 fixed to the shaft 43 at opposite sides of the bearing lugs 16" hold the said shaft against endwise movement. In the present instance thereis secured to the outer face of the needle-guide 44 a loop-engaging finger 51, the point 51 of which is spaced from the point of the finger 44 and passes on the opposite or outer side of the needle 6. The finger 51 is more in the nature of an auxiliary accessory the function of which will be hereinafter referred to.

The loop-deflector with which the present invention is more particularly concerned is preferably made up in the form of a finger or blade 52 which is mounted upon the T- head 53 of a pin 54 journaled in the sleevelike extremity 55 of the bracket 56 secured to the forward arm of the yoke 57, which yoke is freely mounted to rock upon and relative to the shaft 43, as shown in Fig. 2. The forward arm of the yoke 57 is forked at its upper end, Fig. 4, to embrace the cam 58 on t e looper-shaft 16.

Clamped to the lower end of the pin 54 is the split hub end of an arm 59 carrying a ball-stud 60 which is connected by the cylinder 69 fixed to the looper-shaft 16..

The cam 68 serves to rock the finger 62 about the pin 54 as an axis, thereby moving the finger sidewi'se of itself. The cam 58 rocks the finger 52 about the shaft 43, thereby moving such finger endwise of itself. To-

, gether, the cams 58 and 68 move the finger 52 in an orbital path, the shape of which is represented in Fig. 16, such finger moving endwise alongside the needle and then transversely across the path of the needle. The arrow at the left in Fig..16 represents the direction in which the free end of the finger 52 traverses its orbit and the small circles represent the successive positions of the end of the finger 52 for successiye 15 fractions of a revolution of the looper, beginning at zero degrees with the looper-beak in loopseizing position, i. e., when its beak is just passing the needle. It will be noted that the motion of the finger 52 between the 90 and 180 positions is retarded to give theloop-spreading wing 21 opportunity to engage the seized needle-loop before the finger 52 is moved across the needle-path to deflect the limbs of such loop to one side of the needle-path.

Letus now examine Figs. 6 6 and 6, which illustrate the action of the loop-deflector 52 when sewing on a two-hole button; the direction of feed being off of the loppershaft for the particular stitch illustrated. Here it will be seen that the old loop on the looper has been given a half-twist by the looper-wing 21; the limb 71 having been carried outwardly or to the left, Fig. 6* and the limb 71 inwardly. The loop-deflector 52 bends the limbs of the old loop to that side of the needle which the looper passes in seizing a new loop. The upper portions 70 of the old loop, i. e., the portions between the finger 52 and the last stitch in the work, are held in front of the needle-path, Fig. 6 The lower portion of the outer limb 71 of the old loop is held in rear of the needle-path, Fig. 6". The outer edge of the looper-wing 21 is shown in Figs. 6 and 6 as formed with a slight indentation or notch 72 to insure carriage of the limb 71 to the rear of the needleath. This result may obviously be accomplished otherwise than by specially notching the looper. For example, the throat 73 between the Wing 21 and the heel 74 of the looper may be out only to the depth of the notch 7 2, or the looper-shaft may be set with its axis m somewhat to the left of the position shown in Fig. 6 (as disclosed in my Patent No. 1,316,022, of Sept. 16, 1919). It is to be noted that the looperbeak 20 has rotated substantially 270 from button by diagonal crossed stitches, the directions of feed being, respectively, off of the looper-shaft and beak, onto the 1ooper-' shaft and beak, off of the looper-shaft and onto the beak, and onto the looper-shaft and off of the beak.

Figs. 14, 14*, 14 and 14 illustrate the sewing on of a four-hole button by diagonal crossed stitches on a prior art machine, the direction of feed for the particular stitch illustrated being off of the looper-shaft and onto the looper-beak. Figs. 15, 15*, are similar to Figs. 14 and 14, the'direction of feed being onto the looper-shaft and looperbeak.

Fig. 16 is a diagrammatic top plan view illustrating the path of movement of the loop-deflector of the present improvement relatively to the needle.

Fig. 17 is a bottom plan view of a triangular tack as sewed by a machine of the prior art and Fig. 18 is a similar view of a triangular tack as sewed by a machine of the present improvement.

For the purposes of the present disclosure the invention is shown as embodied in a sewing machine having a bed 1, standard 2, and overhanging bracket-arm 3 terminating in a head 4 in which is mounted the vertically reciprocating needle-bar 5 carrying at its lower end the eye-pointed needle 6. The mechanism of the machine is operated by the usual connections with the main shaft 7 on the rearward end of which are mounted the tight and loose pulleys 8, 9, respectively, of a common form of start and stop-motion device including the starting and stopping lever 10 which is pivoted at 11 and carries the belt shipper 12 and stopping tooth 13; the latter cooperating with the stopping cam 14 formed on the hub of the tight pulley 8. The details of this type of start and stop-motion device are more fully disclosed in the patent to Barron, No. 1.093,241, of April 14, 1914. Such device automatically brings the machine to rest with the needle out of the work at the end of each stitching period or after a predetermined number of stitches have been formed.

The reciprocating needle 6 cooperates with the rotary looper 15 mounted on the free end of the looper-shaft 16 which is journaled in the bearing lugs 16, 16 and is connected by bevel gearing 17 to the vertical shaft 18; the latter being geared at 19 to the main shaft 7. The looper has the usual loop-seizing beak 20 and loop-deflecting or loop-spreading wing 21 which operates in a well known manner, after the looper beak has turned about 180 past loop-seizing position, to engage the seized needle-loop and give it a half twist, while retaining control of such loop which is thereafter held spread for passage of the looper-beak with a newly seized needle-loop through the half-twisted and spread needleloop. The old loop is thereupon cast off of the, looper and is drawn up, principally by the action of the looper-beak in distending the new needle-loop.

As is usual in machines of this character,-

mechanism is provided for producing relative movement between the work and needle to group the stitches according to the desired arrangement. This mechanism, which is substantially that disclosed in my patent No. 1,226,963, of May 22, 1917, comprises a feed-wheel 22 mounted in a vertical plane at one side of the standard 2 on a shaft 23 passing transversely through the standard 2 and carrying a gear 24 with which meshes a driving worm 25 on the main-shaft 7. The feed-wheel is formed in its side faces with lateral and longitudinal .feed camgrooves, the longitudinal feed cam-groove ing member of the work-clamp which is spring-pressed toward the work by means of the usual leaf-spring 31. The upper member 30 of the work-clamp may be lifted by the usual connection with a lifting bar 32 which is slidably mounted in the head 4 alongside the needle-bar 5. At its upper end the lifting bar 32 is connected to the treadle controlled clamp lifting lever 33 fulcrumed on the bracket 34, which latter is mounted on the bracket-arm 0.

The machine is preferably equipped with thread cutting and thread gripping mechanism constructed substantially in accordance with the disclosures of my copending applications Serial No. 435,599, filed Jan. 7, 1921, and Serial No. 604,469. filed Dec. 2, 1922. The machine is also fitted with the usual thread-controlling mechanism including a take-up thread-guide 35 mounted on the upper end of the needle-bar 5 and cooperating with a stationary thread-guide 36 mounted on the head 4. The sewing thread is led from the supply through the usual intermittent tension device 37, through the fixed eyelet 38, and thence through the constant tension device 39 to the stationary thread-guide 36 and take-up thread-guide 35 previously mentioned. A pull-01f bar 40 carrying a threaded engaging hook 41 is rigidly mounted on the upperend of the clamp lifting slide-bar 32. The hook 41 is adapted to engage the thread close to the loop-seizing position and that the loopdeflector 52 at this time is moving in the direction of the arrow, Figs. 6, 6 and 6",

wand therefore has a tendency to drag the upper portions 70 of the limbs of the old loop to the front side of the needle-path. The loop-deflector 52 may be slightly hooked or curved at its extremity, as shown in Fig. 6, to prevent the outer limb 71 of the old loop from slipping off the end of the loop-deflector before the point of the needle 6 has descended well below the lead of such limb.

As the looper rotates further from the osition shown in Fig. 6, and approaches oop-seizin position, and just before the needle reac' es the end of its down-stroke, the needle-guide 44 and auxiliary loop-spreader 51 are moved to their operative positions on p opposite sides of the needle 6, Figs. 6 and '6. The loop-deflector 52 has by this time released the limbs of the old loop and the outer limb 71 of such loop is bent around the needle. The inclined face 51" of the loopspreader 51 deflects outwardly the. outer limb 71, Fig. 6, and thus lifts its upper portion higher on the needle so that it will not interfere with the expansion of the inner limb 7 6 .of the new needle-loop. The outer limb 71 of the old loop is also held well .out of range of the looper-beak 20, which must pass between the limbs 71 and 71" of the old loop. The auxiliary spreader 51 is articularly effective when sewing rather ong stitches in directions having a component onto the looper-beak. Its presence serves merely to increase the range of usefulness of the machine and it is not essential to the invention in the broader aspects of the latter. After the old loop is cast off the looper it will untwist and may easily be drawn up as shown in Fig. 6, without, tendency to kink, twist or snarl. In making the next stitch on this particular two-hole button the feed is in the op osite direction or onto the looper-shaft i finger 52 is substantially without function and the stitch will be made without twist, as shown in Fig. 7

Figs. 8 to 9, inclusive, illustrate .the sewing on of a two-hole button when the feed 15 crosswise of the looper-shaft. In Fig. 8-8 the direction of feed is onto the looper-beak or opposite to the direction of feed in ordinary straightaway sewing. Here, the fin er 52 functions to carry the limbs of the old .loop'to the right side of the needle-path, Fig. 8", so that when such loop is cast off of the looper it will be free from twist, as shown in Fig. 8. In sewing the next stitch on this button the direction of feed is off of the looper-beak, as in ordinary straightaway sewin When the feed is in this direction the finger 52 merely moves idly without engaging the limbs of the old loop which need no special manipulation.

'loo er.

Figs. 7-7 Here, the

after being cast off of the looper, as dis-' closed in said Gibbs patent No. 17,427.- Such half-twist will, however, not be apparent at the under side of the work since the crossing point of the limbs of the old loop usually lies at or in the needle-puncture as previously explained.

Figs. 10 to 13 illustrate the sewing on of a four-hole button by crossed diagonal stitches. In Figs. 10 and 10 the feed is diagonal with components directed off of the looper-beak and off of the looper-shaft. The finger 52 is without function and the old loop retains the usual half-twist common to ordinary straightawa sewing. In Fi 11 and 11 the feed is diagonal but in t e op.- osite direction. Here the finger 52 engages the outer limb 71 of the old loop and deflects t sufliciently to insure that it will lie to the inside of the needle-path. The old loop Wlll lose its half-twist when cast off of the 11 Figs. 12 and 12 the'feed is diagonal with components onto the looper-beak and ofl of the looper-shaft. Here, the finger 52 functions substantially the same as in Figs. 6 6 and the upper portions of the halftw1sted needle-loo will lie on the right side of the needle-pat while the lower portion of the outer limb 71 will lie on the left side of the needle-path. The result is that the old loop Wlll untwist after it is cast off of the looper, instead of twisting up further, and may be easily drawn up under a light tension without tendency to kink or snarl. In Figs. 13 and 13 the feed is opposite to that shown in Figs. 12 and 12. Here the finger 52 is without function as in Figs. 10 and 10.

Contrast with Figs. 12 and 12 the action of a machine of the prior art having a looping. The upper portions 80 of the limbs ofthe old loop and the lower portion of the outer limb 81 of such loop, however, lie on the same side of the needle-path, instead of on opposite sides, as shown in Figs. 6 and 12. The result is that when the old loop is cast off of the looper it will in straightening out assume a further halftwist, resultin in a whole twist, as shown in Fig. 14?. his whole twist of the loop interferes with the free and clear drawing up of such loop which latter has a tendency to kink and snarl as it is being drawn up.

onto the looper-shaft.

The friction of the limbs of the loop upon one another increases the tension required to tighten the loop. Figs. 15 and 15 illustrate the conditions in the prior art machine when the feed is dia onal with components directed onto the ooper-beak and loop is without twist.

Fig. 17 shows the appearance of the under side of a triangular tack for paper price marks as sewn on a machine of the prior art. The sewing starts at the point 82 and proceeds to the point 83, the feed being in a direction off of the looper-beak or in the direction of ordinary straightaway sewing. Consequently the loops have the usual halftwist. From 83 the sewing proceeds to 84., the direction of feed being diagonal with components directed onto the looper-shaft and onto the looper-beak as shown in Fig. 15, and the resultant loops are without twist. From 84 to 85, however, the feed is diagonal with components directed onto the looper-beak and off of the looper-shaft, as shown in Fig. 14. Thus the resultant loops are given a full twist and are hard to draw up. Further, they do not ravel easily as is desirable and present an unsightly appearance. From 85 to 82 the sewing proceeds in a direction of ordinary straightaway sewing. In accordance with the present improvement, Fig. 18, the results of-the sewing'from the beginning point 86 to the point 88 will be the same as heretofore, but from 88 to 89 the loops will be free from twist as explained in connection with Figs. 12 and 12 11 comparing the figures, it should be remembered that Figs. 17 and 18 are bottom plan views, whereas Figs. 12 and 144 show the loops viewed from the top or from the position in which Figs. 12 and 14 are viewed. The superiority of the sewin in Fig. 18 over that shown in Fig. 17 wi 1 be apparent.

y virtue of the present improvement remarkably neat work can be done with a single-thread chain-stitch machine when adapted for sewing on buttons, tacking &c. When sewing on buttons the absence of full twists in the loops permits such loops to pack or nest tightly together, thus reducing the size and improving the appearance of the bunch of loops at the under side of the work. Furthermore, weaker and less expensive thread can safely be used since only a light tension is required to snugly set up the loops.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, the combination with .a reciprocating needle, a rotary chainstitch loo er and a looper-shaft, of means for engaglng the limbs of a needle-loop on the looper and moving them in a direction onto the looper shaft.

Here, the resultant 2. In a sewing machine, the combination with a reciprocating needle, a rotary chainstitch looper and a looper-shaft, of means for engaging the outer limb of a halftwisted needle-loop on the looper and moving a bight thereof in a direction onto the looper-shaft.

3. In a sewing machine, the combination with a reciprocating needle and a rotary chain-stitch looper, of a movable loop-deflector acting when the work is fed in a direction having components onto the looperbeak and off of the'looper-shaft to bend and position the limbs of a needle-loop on the looper so that the needle will descend in front of the portion of the outer limb of the needle-loop between the looper and loop-deflector and behind the portions of the limbs of the needle-loop between said loop-deflector and the last stitch.

4. In a sewing machine, the combination with a reciprocating needle and a rotary chain-stitch looper, of a loop-deflector, and means for moving it across the lead of the outer limb of a half-twisted needle-loop on the looper so as to bend such loop across the needle-path and to that side of the needle passed by the looper-beak in seizing a needle-loop, whereby the needle will be caused to descend in rear of the upper portion and in front of the lower portion of the outer limb of said half-twisted loop.

5. In a sewing machine, the combination of a reciprocating needle, a rotary chainstitch looper, and a looper-shaft, of a loopdeflector with means for moving it across the lead of the limbs of a half-twisted needle-loop on the looper in a direction onto the looper-shaft, and means auxiliary to the looper for spreading said loop for entry by the looper-beak with a new loop.

6. The combinationwith a reciprocating needle and a rotary chain-stitch looper, of means for forming a bight in the outer limb of a half-twisted needle-loop on the looper and positioning said bight so that the needle will descend between the upper and lower portions of said limb adjacent said bight.

7. The combination with a reciprocating needle, a throat-plate, and a rotary chainstitch looper, of means between the throatplate and the looper for forming a bight in the outer limb of a half-twisted needleloop on the looper and positioning said bight so that the needle will descend between the upper and lower portions of said limb adjacent said bight.

8. The combination with a reciprocating needle and a rotary chain-stitch looper, of a four-motion loop-deflector in the form of a finger having its extremity pointed in the general direction of movement of the looperbeak when seizing a needle-loop, and means for moving said loop-deflector in an orbital path embracing the needle-path.

9. The combination with a reciprocating needle, a rotary-looper shaft, and a looper mounted on such shaft, of a four-motion loop-deflector in the form of a finger and tary chain-stitch looper, a work-holder,-

means for relatively moving the stitchforming mechanism and work-holder to sew a group of stitches, and movable means below the throat-plate adapted to engage the outer limb of a half-twisted needle-loop on the looper, when the feed has a component directed onto the looper-beak, and bend said limb between its ends in a direction onto the looper-shaft and across the needle-path, whereby the needle will descend behind the upper and in front of the lower portions of such bent loop.

11. In a sewing machine, the combination with a reciprocating needle, a.looper and a looper-shaft, of a loo -deflector, a carrier on which said loopeflector is movably mounted, said carrier being mounted to rock on an axis parallel to the looper-shaft and having a forked portion, a cam on the looper-shaft and connections for rocking the loop-deflector relative to its carrier, and a second cam on said looper-shaft embraced by the forked portion of said carrier.

12. In a sewing machine, the combination with a reciprocating needle and a rotary chain-stitch looper, of means acting during the formation of a back-stitch to carry a bight of the outer limb of a half-twisted needle-loop on the looper to that side of the needle passed by the looper-beak, and means at the opposite side of the needle for moving the needle-engaging portion of said outer limb toward the throat-plate to give the newdneedle-loop increased freedom to expan In testimony whereof, I have signed vmy name to this specification.

ALBERT F. FIFIELD. 

